Re: BUG #1208: Invalid page header

Dear Tom,
	Besides a no optimization compilation of 7.4.3, what else
would you recommend to explore this problem further? Thanks. --Bob

Tom Lane writes:
> 
> 
> "Robert E. Bruccoleri" <bruc@stone.congenomics.com> writes:
> > 	Question: were there any significant changes made to the
> > buffer management code between 7.4 and 8.0 that would explain the
> > difference?
> 
> There are some nontrivial changes, but none that I would regard as
> likely to cause a multiprocessing error to magically go away.  More
> to the point, if there is such a bug in 7.4.3 there's no guarantee
> it won't come back again.
> 
> > 	I haven't tried rerunning 7.4.3 without optimization to see if
> > the problem disappears in that release. Since the 8.0beta1 release
> > appears OK, and the test run takes about three days, so I'm reluctant
> > to do it unless there's some value in performing test. Please tell me
> > if there is.
> 
> If you believe this is not a hardware problem, you'd better keep
> digging.  There is no known reason for 7.4 to fail like that.
> It would be folly to assume that we've fixed the problem without
> knowing it.
> 
> > 	Another question: on a machine which has this high level of
> > parallelism, does it make sense to use a spinlock to control access to
> > the buffer cache instead of a lightweight lock?
> 
> No.  The angst you've probably been reading is focused around the
> spinlock part of the LWLock --- simplifying the LWLock to a bare
> spinlock will not improve matters.
> 
> 			regards, tom lane
> 

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